川江流域洪涝成因分析     

贺素娣 《山地学报》1991,(2)

川江流域洪涝频繁而危害大。兹以旬、两旬雨量分别为250—350,350—500毫米作主要洪涝指标。流域内洪涝频率、大面积洪涝频率的分布区域差异明显。洪涝的形成受暴雨和大地形结构控制,此外还受四川盆地地形、水系结构与森林遭破坏等的影响。  相似文献   

山阳－柞水隐爆角砾岩与金矿化关系及其成因初探     

谢茂祥 《河南国土资源》1994,(4)

本文总结山阳—柞水地区隐爆角砾岩（以下简称角砾岩）的基本特征及其与金矿化关系，此角砾岩是区内重要含矿岩石。讨论了角砾岩的成因、含矿性和形成机制。  相似文献   

福建何宝山金矿成因探讨     

林仟同 《福建地质》1993,12(4):239-247

福建何宝山金矿的成矿地质条件在崇安—石城构造带,特别是中、南段金矿中具有广泛的代表性。本文从矿区宏观地质特征入手,结合成矿元素构造地球化学研究、氢氧硫同位素特征以及K-Ar年龄证据等。认为何宝山矿区金矿化主要经历了加里东期断裂变质-混合岩化作用和(印支晚期)—燕山早期构造动力作用两次叠加、富集成矿过程,前者是金富集成矿的“基础”,后者是形成具一定工业意义金矿体的“关键”。  相似文献   

再论蛇屋山红土型金矿的成因   总被引：10，自引：1，他引：9  

李松生 《矿床地质》1998,17(2):114-124

蛇屋山金矿是我国第一个大型红土型金矿床。它具有规模大、品位低、易采、易选、经济效益好等特点,是黄金矿业中建设大型露采堆浸场的理想基地。这个矿床的成矿物质来自奥陶系碳酸盐岩硅化破碎带,成矿活动以第四纪化学风化作用为主。在中更新世热带雨林条件下,在岩石的红土化过程中,金从原岩中析出,与风化产生的铁质水溶液一起,沿着红土裂隙向下渗透,停积于地下潜水面,形成似层状矿体。  相似文献   

广东梅县嵩溪Ag（Sb）矿床特征及成因探讨   总被引：4，自引：1，他引：3  

蒙晓莲  汪礼明 《华东地质学院学报》1998,21(1):52-62

广东梅县嵩溪Ａｇ（Ｓｂ）矿床,位于广东东北部、蕉梅凹陷区内,中生代寨岗上火山喷发沉积盆地的北部边缘外侧。本文在研究矿床特征的基础上,着重研究了矿床成因特征,并做了成矿模拟实验,提出了该矿床是一个火山喷流沉积－热液改造的大型Ａｇ（Ｓｂ）矿床。火山喷流沉积大约发生于１５４Ｍａ（相当于下侏罗统）,热液改造发生在上侏罗统大规模火山活动时期,是一个具有重要经济价值和理论意义的低温Ａｇ矿床。  相似文献   

Granulite Genesis and Tectonic Evolution in Tongbai Area: Single Zircon Evaporation Ages and Nd Isotopic Geochemistry   总被引：1，自引：0，他引：1  

Zhang Hongfei  Gao Shan  Zhang Li 《中国地质大学学报(英文版)》1998,9(3):217-222

ＩＮＴＲＯＤＵＣＴＩＯＮＴｏｎｇｂａｉａｒｅａｉｎＣｅｎｔｒａｌＣｈｉｎａｉｓａｎｉｍｐｏｒｔａｎｔｒｅｇｉｏｎｆｏｒｓｔｕｄｙｉｎｇｇｅｎｅｓｉｓｒｅｌａｔｉｏｎｂｅｔｗｅｅｎＱｉｎｌｉｎｇｏｒｏｇｅｎｉｃｂｅｌｔａｎｄＤａｂｉｅｏｒｏｇｅｎｉｃｂ...  相似文献   

巴塘县夏塞蓝刚玉矿地质特征     

侯浩 《四川地质学报》1998,(3)

对蓝刚玉矿的地质特征、矿石类型及蓝刚玉特征作了简述,并对蓝刚玉的成因进行了初步探讨,提出了找矿标志。  相似文献   

河北丰宁大营子一带金矿成矿地质条件及成因   总被引：1，自引：0，他引：1  

胡醒民 《黄金地质》1998,(1)

丰宁大营子一带大面积出露古元古代闪长岩和海西期二长花岗岩。两期侵入体的接触带附近金矿（化）点发育,并呈北东向带状集中分布于海西期侵入体的外接触带内。本区矿源、热源、水源都很丰富,成矿地质条件优越,具成矿远景,矿床成因与成矿规律符合“三源”成矿模式。  相似文献   

Geology and Origin of the Dongping Alkalic-Type Gold Deposit, Northern Hebei Province, People's Republic of China   总被引：6，自引：0，他引：6  

Feng–Jun NIE 《Resource Geology》1998,48(3):139-158

Abstract: The Dongping deposit, located near the center of the northern margin of the north China craton, is one of the largest gold deposits in China. It is spatially, temporally, and genetically associated with the shallowly-emplaced Hercynian Shuiquan-gou alkaline intrusive complex. The complex intrudes high-grade metamorphic rocks of the Archean Sanggan Group along a deep-seated fault zone within the north China craton. Four major ore bodies (Nos. 1, 2, 22, and 70), consisting mainly of a set of en echelon lenses and veins, have been delineated at the Dongping deposit. Hypogene hydrothermal activities can be divided into four periods from early to late including: (1) gold-bearing K–feldspar–quartz stockworks and veins; (2) disseminated sulfide and gold zones; (3) gold-bearing quartz veins, and (4) barren calcite-quartz veins. Individual veins and stockwork systems can be traced along strike for 125 to 600 m and downdip for 100 to 600 m; they range from 0. 5 to 3 m in thickness. The mineralogical composition of the ore in the first three hypogene periods is relatively simple. It is composed of pyrite, galena, sphalerite, magnetite, specularite, chalcopyrite, native gold, electrum, calaverite, and altaite. Gangue minerals include K–feldspar, quartz, sericite, chlorite, epidote, albite, and calcite. Ore grade averages 6 g/t Au, but varies between 4. 14 and 22. 66 g/t Au. Gold is generally fine-grained and not visible in hand specimen. Fluid inclusions in ore-bearing quartz of periods 1, 2, and 3 are CO₂–rich, variable salinity (2. 5–21 wt% equiv. NaCl), and have variable homogenization temperatures of 195° to 340°C. Quartz in the gold-bearing K–feldspar–quartz stockworks (period 1), disseminated sulfide and gold zones (period 2), and the gold-bearing quartz veins (period 3) has calculated δ¹⁸O_H2O values between –1. 7 and 6. 9%, and δ values of fluid inclusion waters between –101 and –66%. All these isotope data of the ore-forming fluids plot between the magmatic fluid field and the meteoric water line. Sulfide minerals disseminated in host rocks show positive δ³⁴S values of 1. 9 to 3. 5%. Pyrite separates from he gold-bearing K–feldspar–quartz stockworks and veins (period 1) have a δ³⁴S range of –4. 3 to 0. 5%, whereas δ³⁴S values of pyrite, chalcopyrite, galena, and sphalerite from the disseminated sul-fide and gold zones (period 2) and the gold-bearing quartz veins (period 3) vary from –5. 3 to –13. 4%. Gold ores are also characterized by relatively radiogenic lead isotope compositions compared to those of the alkaline syenite host rock. The data are interpreted as indicative of a mixing of lead from the alkaline intrusive complex with lead from Archean metamorphic rocks. The combined fluid inclusion measurements, sulfur, oxygen, hydrogen, and lead isotope data, and petrological observations indicate that the Dongping deposit was formed from the mixing of these magmatic fluids with meteoric waters. The deposit is, therefore, believed to be a product of Hercynian alkaline igneous processes within the north China craton.  相似文献   

靖州平茶金矿地质特征及成因探讨   总被引：7，自引：0，他引：7  

胡清洁 《湖南地质》1998,17(1):28-33

靖州平茶金矿为多硫化物型锑金矿床,矿经受近东西向次级断裂和蚀变带控制,矿床规模小,但品位高。系深源岩浆水和浅变质水二元混合成矿作用而成。  相似文献